For a quadratic equation of the form \(y = k{(x - a)^2} + b\), the following diagram shows the main properties: If k > 0, the vertex is a minimum turning point If k < 0, the vertex is a maximum ...

The equation of a straight line can also be written in the form \(f(x) = mx + c\). This is called function notation and is just another way of expressing the relationship between two variables.